1. Field of the Invention
The present invention relates to an electrolytic sterilizer for contact lenses comprising a main body accommodating a power source unit and a sterilizing container detachably mountable on the main body. More particularly, the present invention relates to a specific structure for the electrode connection in such an electrolytic sterilizer.
2. Description of the Prior Art
Conventional hydrated contact lenses composed principally of a hydrophilic monomer such as 2-hydroxyethyl methacrylate normally contain more than about 30% by weight of water. As a result, the hydrated contact lenses are likely to provide by themselves a favorable environment for the multiplication of various detrimental bacteria. Furthermore, it is very dangerous to wear bacteria-infected contact lenses on the eyes without treating them in any way, since this practice may lead to serious damage to the eye tissue. For this reason, it is essential to sterilize such hydrated contact lenses periodically.
For example, the most common method for sterilizing the hydrated contact lenses is a method wherein the lenses are boiled for a predetermined time. This method is extremely effective for sterilizing the lenses, but at the same time it has the following serious disadvantages, which may be regarded fatal defects:
(1) The protein and other components in tears deposited on the lens undergo a thermal metamorphosis due to the boiling operation and stick to the lens surface, thereby impairing the optical properties of the lens and remarkably reducing the comfortableness of wearing the lens on the eye.
(2) The sparingly cross-linked hydrophilic polymer, which is the material of hydrated contact lenses, is likely to deteriorate due to repeated severe boiling treatments. Thus, the lens is subject to discoloration and/or change in standard configuration, thereby resulting in reduced useful life of the lens.
(3) Boiling sterilization may not be accomplished on non-hydrated contact lenses which are composed of polymethyl methacrylate and/or silicone rubber.
In order to alleviate the drawbacks associated with boiling sterilization, it has been proposed to employ a method wherein the contact lenses are sterilized by various disinfectant fluids such as solutions containing, e.g., thimerosal or chlorohexadine. In such a treatment, the disinfectant component will readily be adsorbed into the lens body because of the large structural spaces between molecules constituting the hydrated contact lenses. However, the adsorbed disinfectant component has the potential danger of causing hypersensitive inflammation to the eye tissue.
There has also been proposed a method wherein the lenses are sterilized with a 3% aqueous solution of hydrogen peroxide, and then the solution is contacted with a catalyst such as platinum to decompose and detoxicate the hydrogen peroxide into water and oxygen. This method also has disadvantages in that it requires a considerably longer time in sterilization and is impractical because of its complicated operation.
Further, Japanese Unexamined Patent Publication No. 68454/1981 discloses a method wherein contact lenses kept in a container filled with a physiological sodium chloride solution are sterilized and disinfected as they are kept in the container. The sterilization and disinfection is accomplished by electrolyzing the physiological sodium chloride solution to form an effective amount of sodium hypochlorite as a disinfectant. An electrolytic sterilizer for contact lenses of this type comprises a main body accommodating a power source unit, a sterilizing container detachably mountable on the main body, and a structure for electric connection, which is provided at the joint portion. The structure for electric connection in this type of sterilizer comprises base body-side contacts formed of a material such as conductive rubber in a recess of the main body designed to receive the sterilizing container. If the physiological sodium chloride solution to be used for sterilization or the sodium hypochlorite solution obtained by the electrolysis is deposited or dropped in a small amount and if the sterilizing container is connected for sterilization, electrolysis takes place between the body side contacts, whereby the electrolysis in the sterilizing container will be disturbed or impaired and a disinfectant solution having an adequate concentration will not be formed. Accordingly, if the contact lenses are washed and sterilized with such a disinfectant solution, no adequate effectiveness will be obtained, and if such contact lenses still infected with bacteria are worn, there will be a possible danger of hurting the eyes. Further, there is an additional drawback that the contacts are likely to wear out as a result of the electrolysis which takes place between the contacts on the main body side.